[FFmpeg-cvslog] avcodec/pngdec: Check IHDR/IDAT order

[Michael Niedermayer]

ffmpeg | branch: release/2.3 | Michael Niedermayer <michaelni at gmx.at> | Wed Nov 26 15:45:47 2014 +0100| [1bfd23d2c934db2f7fc20c1e4de5404869555991] | committer: Michael Niedermayer

avcodec/pngdec: Check IHDR/IDAT order

Fixes out of array access
Fixes: asan_heap-oob_20a6c26_2690_cov_3434532168_mail.png
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
(cherry picked from commit 79ceaf827be0b070675d4cd0a55c3386542defd8)

Conflicts:

	libavcodec/pngdec.c

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=1bfd23d2c934db2f7fc20c1e4de5404869555991
---

 libavcodec/pngdec.c |    6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c
index 8f3da77..5e62a60 100644
--- a/libavcodec/pngdec.c
+++ b/libavcodec/pngdec.c
@@ -576,6 +576,12 @@ static int decode_frame(AVCodecContext *avctx,
         case MKTAG('I', 'H', 'D', 'R'):
             if (length != 13)
                 goto fail;
+
+            if (s->state & PNG_IDAT) {
+                av_log(avctx, AV_LOG_ERROR, "IHDR after IDAT\n");
+                goto fail;
+            }
+
             s->width  = bytestream2_get_be32(&s->gb);
             s->height = bytestream2_get_be32(&s->gb);
             if (av_image_check_size(s->width, s->height, 0, avctx)) {